[ncl-talk] avoiding loops

Mon Sep 23 11:00:12 MDT 2019

NCL wont allow me to use i5 format on the variable. I've used the
floattointeger, but when I print that variable, it still shows that is of
type float, even though the values were properly converted to integer.

On Mon, Sep 23, 2019 at 12:57 PM Dennis Shea <shea at ucar.edu> wrote:

> *  fmtf*
>
> Format to be used, specified *via Fortran style*. The format string used
> must agree with the variable type.
>
> ===
>
> Google fortran edit descriptors..
>
> "384(f0.1,','),f0.1"
>
> "384(i5,','),i5"
>
> On Mon, Sep 23, 2019 at 12:43 PM Micah Sklut via ncl-talk <
> ncl-talk at ucar.edu> wrote:
>
>> This worked great Dave. I appreciate the great support. I did the
>> asciiread to read back in all the string arrays, and then used write_table
>> to format the final output.
>>
>> One last question. When formating the write_matrix calls, I'm trying to
>> write a float variable to integer format.  When I use, floattointeger
>> function, it properly converts the values to integers, however, it doesn't
>> change the variable type in the metadata from float to integer. This
>> doesn't allow me to write_matrix using integer format. Is there an easy way
>> to get around this?
>>
>> On Sun, Sep 22, 2019 at 8:31 PM Dave Allured - NOAA Affiliate <
>> dave.allured at noaa.gov> wrote:
>>
>>> Write_matrix is strictly for output to only a text file, or Unix
>>> standard output.  There is no internal write capability.  However, you can
>>> simulate internal writes by using one or more temporary files.
>>>
>>> Read the formatted lines back in from a temp file with asciiread
>>> ("tmp.txt", -1, "string").  This gives you a 1-D array of strings, one full
>>> line for each of your grid points.  Then repeat for each of your other
>>> variables.  This will efficiently give you arrays of full formatted line
>>> strings for several variables.
>>>
>>> You should then be able to join these line strings together, however you
>>> have in mind.  Also, now that you are operating on strings, you can add
>>> text columns at the beginning or end of each string, if this would be of
>>> any help.  For example:
>>>
>>> long_lines = "precip," + p_lines(:) + ",Tmin," + tmin_lines(:) +
>>> ",Tmax," + tmax_lines(:)
>>>
>>> This example is for joining horizontally.  You could also join
>>> vertically by simply joining the string arrays, with or without
>>> interleaving.  There are many variations on this theme, depending on how
>>> you want your final output to be structured.
>>>
>>>
>>> On Sun, Sep 22, 2019 at 5:29 PM Micah Sklut <micahs2005 at gmail.com>
>>> wrote:
>>>
>>>> Instead of sending output to a file, is it possible to do a
>>>> write_matrix formatting to 1d array?  I need to add more than 1 of these
>>>> variables together, so if I can create 1d arrays for all of the variables
>>>> and metadata, such as lat/lon, then I can use write_table to join
>>>> everything together. When I'm re-ordering or reshaping the arrays, I'll
>>>> just need to delete the old arrays, to free up memory.
>>>>
>>>> On Sun, Sep 22, 2019 at 1:51 PM Dave Allured - NOAA Affiliate <
>>>> dave.allured at noaa.gov> wrote:
>>>>
>>>>> There is a mistake in the untested example that I sent.  Please change
>>>>> the format spec from "384(f0.1,','),f0.1" to "383(f0.1,','),f0.1".  The
>>>>> latter is correct for 384 numbers per line.  I split the format spec into
>>>>> two parts so that there would not be a trailing comma at the end of each
>>>>> line.
>>>>>
>>>>> Generally speaking, the format spec in write_matrix is specified for a
>>>>> single output line.  It is repeated for each output line.  It is important
>>>>> that the total item count in the format spec (383 + 1 in this case) exactly
>>>>> matches the intended number of items per line.
>>>>>
>>>>>
>>>>> On Sun, Sep 22, 2019 at 11:32 AM Micah Sklut <micahs2005 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Okay, thanks, Dave.  That sounds like what I need. I've always
>>>>>> struggled with the formatting in NCL, but I'll give that a go and see where
>>>>>> I get.
>>>>>>
>>>>>> On Sun, Sep 22, 2019 at 1:26 PM Dave Allured - NOAA Affiliate <
>>>>>> dave.allured at noaa.gov> wrote:
>>>>>>
>>>>>>> Try write_matrix and the F0 format descriptor.  F0 format is part of
>>>>>>> fortran 90 and up.  It is described in modern fortran documentation.  It is
>>>>>>> like the common Fw.d format descriptor, except leading blanks to the left
>>>>>>> of the decimal point are suppressed.
>>>>>>>
>>>>>>> Reshape your array from, e.g. (lat,lon,time), to a 2-D array in the
>>>>>>> desired output order, (points,time).  Npoints = Nlats x Nlons.  Then a
>>>>>>> single call to write_matrix should write the entire output file:
>>>>>>>
>>>>>>>     opt = True
>>>>>>>     opt at fout = "temperature.csv"
>>>>>>>     write_matrix (data_out, "384(f0.1,','),f0.1", opt)
>>>>>>>
>>>>>>> You can add arbitrary extra numeric columns to the output array, if
>>>>>>> it would be helpful to have lats and lons, or other such metadata, on each
>>>>>>> line of output.
>>>>>>>
>>>>>>>
>>>>>>> On Sat, Sep 21, 2019 at 2:53 PM Micah Sklut via ncl-talk <
>>>>>>> ncl-talk at ucar.edu> wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> I have a task to take GFS data and concatenate variables across all
>>>>>>>> the forecast hours, for each grid point.
>>>>>>>>
>>>>>>>> For example, taking a temperature variable for each grid point, for
>>>>>>>> all latitude and longitudes, and creating a string that represents the
>>>>>>>> values for each forecast hour.
>>>>>>>> So, if we have for latitude y, and longitude x, there would be a
>>>>>>>> string value like "70.5,71.5,71.5,72.0,...nHours".  The end product will be
>>>>>>>> a line for each grid point for the variables i"m looking at that will be
>>>>>>>> written to a file to be imported into a database.
>>>>>>>>
>>>>>>>> Creating loops through all hours, latitudes, and longitudes will
>>>>>>>> get the job done, but is expensive and was looking to see if there were any
>>>>>>>> NCL functions that would help here.
>>>>>>>>
>>>>>>>> Thank you.
>>>>>>>>
>>>>>>>
>>
>> --
>> Micah Sklut
>>
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>
>

-- 
Micah Sklut
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